The maximum attachment size in MB. [upstream issue comment]: https://github.com/roundcube/roundcubemail/issues/7979#issuecomment-808879209 Since there is some overhead in base64 encoding applied to attachments, + 37% will be added to the value set in this option in order to offset the overhead. For example, setting maxAttachmentSize to 100 would result in 137M being the real value in the configuration. See [upstream issue comment] for more details on the motivations behind this.

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